Tidy up the name of Deploy.sim_cfg #164
Description
... since it's not actually a SimCfg!
A trivial (but slightly noisy) change is to rename it to flow_cfg. While we're doing that, we can also get rid of the rather ugly _typed_sim_cfg that I had to add to some of the classes (and call that just sim_cfg).
@AlexJones0 had some further ideas of how to do this cleanly in this comment.